ML server how to?

I'm new to MacOsX server. Actually just wanted to learn about it, how to use, what can I do with it... I got documentation for it, read it through. So I got the server.app, installed it on my running ML system. As I read it it supposed to be really easy to set the things up. Just wanted to set up a server allowing Local Network and VPN connections. I don't need registered domain name for that just my local host name like server.local or server.example.private for the VPN. After this step I allowed the server.app to manage my time capsule and after the Push Notification window I got this message: 'A server with the specified hostname could not be found.' And the whole installation process stops. What did I do wrong? The host name is working, checked in terminal with ping. Tried to look it up on several forums, I couldn't find my answer.
I hope somebody can help me...

MacRumors attracts a broad audience
of both consumers and professionals interested in
the latest technologies and products. We also boast an active community focused on
purchasing decisions and technical aspects of the iPhone, iPod, iPad, and Mac platforms.